A Model for Feedback-Stabilization in Sillenites

When recording phase volume holograms in photorefractive crystals, stabilization is often desirable so that the external conditions are constant during recording. A method of stabilization by using phase modulation in a feedback loop has been developed by Frejlich and Kamshilin. The method has been applied to LiNbO3, yielding the surprising side effect that for a large range of experimental parameters a diffraction efficiency, η, of 100 % could be achieved.1 Experiments have also been performed in the sillenites.2 There such a large diffraction efficiency is of course not possible, but there is another welcome side effect: by changing experimental parameters the detuning frequency, Ω, between the signal wave and the pump wave could be given an arbitrary value. As a consequence, the resonance of diffraction efficiency and gain as a function of detuning, fundamental for all applications of sillenites, can be exploited in experiments which at the same time are run stabilized.